The Eye in its Relation to Health
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By Chalmer Prentice, M.D.
Chicago, A.C. McClurg & Company, 1895
Transcription (c) A. Wik, 2004

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        | Chapter X |  pages 153-164
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								153

THE short or stretched muscles never assume
much if any normal action.  They are
always being stretched and relaxed again, conse-
quently they are thin, attenuated, and undevel-
oped.
  Under this irregularity condition, the most deli-
cate correlated action exists in the various move-
ments of the eye, just as if perfect anatomical
conditions existed.  The nice relation existing
between the accommodative effort of the ciliary
muscles and the relative convergence of the optic
axes to fix them for various distances, is main-
tained to a mathematical nicety.  In exophoria,
where convergence is performed by a contraction
of the internal recti, and divergence is performed
by a relaxation of the same, it is the amount of
innervation sent to the interni that in part estab-
lishes our judgment of distance.  In a marked
case of esophoria or short internal muscles, where
the act of divergence from the near point to par-
allelism is performed by an excessive contraction
of the external muscles, and convergence to the
near point by a relaxation of the same, it is the
variation of innervation to the external muscles

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combined with the effort of the ciliary muscles
that determines our judgment of distance.
  In esophoria, or convergence due to short
internal muscles, where their length is such that
the optic axes would be converged for a distance
of ten or twelve inches during the absence of
innervation, it is through the agency of nerve-
impulse to the external muscles that the optic
axes are drawn into parallelism for distant vision;
and when the near point is again sought and the
ciliary accommodation increases the refraction,
it is not as has been generally assumed, an asso-
ciated contraction of the internal muscles that
converges the eyes; it is a negative action, a sus-
pension of innervation to the external muscles.
  The nice and delicate correlated action of the
various parts of the eye has been assumed by
some to be a delicacy of mechanical balance of
the various muscles, but this is seldom if ever
true.  In nearly all cases, the balance is main-
tained by innervation which is the outgrowth of a
stimulus in the nerve-centers for perfect vision.
In such cases, the abnormal nerve-impulses have
continued so long in the performance of their
various duties, that they have become fixed
impulses and they are virtually interlocked with
each other.
  There are numerous cases of defective eye-
balance where short and abnormally innervated

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muscles exist in one or more situations which
seem to be firmly and most fixedly locked
throughout, one with the other.  To make myself
thoroughly understood, I will assume to know
just how much tendency to deviation there is in a
given case in the absence of innervation.  The
left superior is short enough to cause the eye to
deviate 6 deg. upward, and the two externals 20 deg.
outward, while the ciliary is making up for 3 diop-
tres of latent hyperopia.  All of these conditions
are latent.  Excessive innervation of the inferior
muscle pulls the eye down against the short
superior; abnormal innervation to the interni
draws the eyes to a balance against the short
externals, and the ciliary at the same time is mak-
ing up the 3 dioptres of deficient refraction in the
crystalline lens, until the function of perfect vis-
ion is the result, and all defects are hidden.
It sometimes is a very tedious and puzzling
problem to upset or unlock this correlated con-
dition of abnormal impulses, and reveal the
defects.  If the abnormal innervation of one of
these muscles can be interfered with and broken,
there will be a general unfolding of all the
defects.  It is sometimes difficult to know where
to begin.  A few hours' or days' fogging may
relax the ciliary spasm, and, after it has yielded,
defects in other muscles will begin to manifest
themselves; then development in that particular

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direction may be taken up and followed until
the condition of the eye is revealed with abso-
lute certainty, by careful adherence to symptom
tests.
  Sometimes the ciliary spasm does not readily
yield to fogging, in which case it may be easier
to discover some defect in one of the long
muscles, for illustration, the left superior.  In
                this case an examination with dots
                or lights might show the two
                objects to be perfectly horizontal,
                or so nearly so that the patient
                could not discern that one light
   [chart]      was higher than the other.  By
                using a chart with a star or dot in
                the middle, and lines drawn hori-
                zontally across the chart both
                above and below the dot, equi-
                distant from each other so as to
                represent for each space 1 deg. at
                the distance of examination.  By
the use of a 5 deg. prism, base down, first before
one eye and then before the other, there will in
each position appear to be two stars, with possi-
bly four lines between the stars in each posi-
tion.  We then reduce the prism to 4 deg. and
find the same result; then to 3 deg., where we
may possibly find that a difference will manifest
itself.  That is, with the prism, base down,

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before the right eye there will perhaps be two
stars, while before the left eye there will appear
only one.  Or, if there be no difference with
the 3 deg. prism, we resort to a 2 deg. prism,
with which, if there is any difference, we shall
discover it by there being perhaps two stars
before the left eye with no lines between, while
before the right there may be two stars with one
line between; or we may have to use a 1 deg.
prism before we find the difference, which will
possibly be fusion before the left eye, while there
are two stars with the same prism, base down,
before the right.  Perhaps even here the only
difference that can be noted will be that the vision
is much more perfect with the 1 deg. prism, base
down, before the left eye and more indistinct in the
same position over the right.  We can then place
in our trial frame a 1 deg. prism, base down,
before the left eye.  In ten minutes, more or less,
the same eye will be able to accommodate itself
for 2 deg., and a little later for 3 deg., 4 deg., and 5
deg., and so on up sometimes to 8 deg. or 10 deg.
within an hour or two, while at the beginning the
eyes could not accommodate themselves to 1 deg.
or 2 deg. of prism in the same position.  The sur-
mounting of this difficulty will sometimes cause a
tonic unyielding spasm in the ciliary to begin to
manifest itself, where it would not readily do so
as represented above by fogging.  It may also

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unfold some defect in the internal or external
muscles.
  We can with advantage oftentimes carry on
repression in three directions at the same time.
For instance, as in case 11, page 105, ciliary
repression with +3D spherical, left inferior rectus
14 deg., base down, with 18 deg., base in.  The
suspension of repression in any one of these three
directions in this case materially aggravated the
symptoms.  Inasmuch as fogging diminishes the
fusion stimulus for the distance, we are often
obliged to sacrifice some repression in this direc-
tion for the purpose of increasing it in another,
or to increase repression in this direction by
sacrificing it in another.  Extraordinary care,
patience and judgment are necessary at all times
in the process of repression.  Considerable
variations in the condition of the nerve-centers
ranging from depressed to more exalted states,
often oblige us to retreat by reducing our prism
in one or more directions for the purpose of
remaining within the range of fusion.  In some
cases this will occur repeatedly, and at times may
have a tendency to confuse us.  Such circum-
stances should make us doubly careful, but should
not deter us from attacking the same position
again as soon as practicable.
  The following is a continuation of the test of
the vertical muscles where they will accommodate

								159

for larger amounts of prism.  It has been a com-
mon practice to use a 3 deg. prism, base down,
first before one eye and then before the other.  If
fusion takes place in both these positions, the
inference has been that there is nothing defi-
cient in a superior or inferior muscle; but this
conclusion is erroneous, for serious defects may
exist without the above test giving the slightest
indication of it.
  When fusion takes place with a 3 deg. prism,
base down, before either eye, we should next re-
sort to a 4 deg. prism.  If fusion takes place with
this, we should then use a 5 deg., and continue to
increase the power of the prism until the highest
degree is reached where fusion will take place.
It may be six, seven or even more degrees, and if
fusion takes place before one eye equally with
the other, there is apparently no difference as
recorded by this test.  If, on arriving for instance,
at a 7 deg. prism we find it will fuse before the
left and constantly refuse to do so before the
right eye, we assume to have discovered a short-
ness in the muscle toward the apex of the prism
where the highest fusion takes place. and the cor-
rectness of our inference should always be verified
by symptom tests.
  Now, before the eye that fuses for the highest
degree of prism, we continue to add more, until
we have reached the highest number of degrees

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under which fusion will take place, which may
possibly be ten or more degrees of prism more
than the opposite eye would fuse for.  If any
such result is obtained, we should take off all
prism for a time and repeatedly endeavor, by
careful coaxing, to see if the eye that accepted
the less prism can in any way be drawn to take
on an equal amount with the other eye.  If it
persistently refuses to do so, we should then
apply to the other eye all that it will accept.
During this time we should constantly observe
what changes, if any, take place in some promi-
nent symptom or symptoms of the patient's dis-
order.  If there be a marked change for the better
in the action of the heart, or in some other con-
dition, it is evident that we are turning the eye in
the direction of the short muscle and repressing
the abnormal innervation in the opposite; but if
the disturbed conditions are emphasized as we
proceed, it is very evident that the eye is being
turned in a wrong direction and that we are being
led on by a short muscle, the shortness of which
is due to spasm and not an anatomical defect.  In
this case we are increasing the abnormal innerva-
tion and the irritation of the nerve-centers.
  During our first efforts at repression we may
not at once effect sufficient change in the dis-
turbed conditions of the patient to assure us that
our repression is correct, in which case we should

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turn our test prism in the opposite direction; then
if all the unfavorable symptoms be aggravated,
we have some assurance at least that the last
position was wrong, and therefore we return to
the first position and proceed with caution and
patience.
  During all tests the color of the skin, the
action of the heart, the warmth of the hands and
feet and the general feelings of the patient should
be carefully inquired into, for sometimes a spasm
will turn the eye 8 deg. or 10 deg. in a direction
opposite to the short muscle.  The only safe way
of discovering this spasm is to note the symptoms
of the patient as we proceed, exercising at all
times the greatest care in drawing our conclu-
sions; for a pleasant stimulated feeling sometimes
follows the turning of the eye in the direction of
the spasm; but such a change is of a temporary
character, and a few hours or a few repetitions of
the experiment will suffice for the manifestation
of unfavorable symptoms.  Again, when we are
developing in the proper direction, disturbances
of a transitory character will sometimes arise, but
these are not an aggravation of the symptoms of
the disease.  They should always be subdued.
If we are really repressing, the probability is that
the temporary disturbances arising are all new
symptoms.  The exceptions exceed any general
rule that can be laid down in this practice, and
	11
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each case presents features that require individual
care.
  Sometimes we may be fortunate enough to
have such marked changes ensue from repression
that there will be little uncertainty.  I have seen
it reduce the heart's action within one hour from
120 to 65, where on the removal of the glasses the
heart in a short time would increase to its former
standard, and again with the glasses be reduced.
I have repeatedly seen persistent pains in the
back, the ovaries, the stomach and various other
parts relieved within an hour or two, and repro-
duced by the removal of the glasses or the
reversal of the prisms.  I have seen the reverse
position produce a nervous chill.  There cer-
tainly is as much mental-suggestion in one posi-
tion of the prism as the other.
  There may be fully as much consciousness of
effort in a repressive strain that suspends impulse
as if it were a direct one requiring innervation to
sustain it.
  During repression, when the excessive impulse
has been partially suspended, it will sometimes
suddenly return, and with it the disturbing and
annoying symptoms of the disease will be aggra-
vated, but we must not be misled by this, for it
is a thing of frequent occurrence.  Abnormal
innervation is very obstinate and is repressed
slowly.  The longer repression is persisted in, the

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less likely is spasm to occur; but, when it does,
the patient is unable to fuse any longer under the
prism which was worn just before its return.  In
this case the prism should be reduced to a pos-
sible point of fusion again, for if the full
amount is continued the fusion stimulus is lost
and the spasm runs riot; but if the prism is re-
duced to that point where fusion can take place
again, the spasm will be held more or less under
subjection, after which we can gradually increase
the prism again to the point where the spasm oc-
curred, and in time get beyond it.  These annoy-
ances occur far short of full development, with
only 2 deg., 3 deg. or 4 deg. of prism, where
later the same case may develop 15 deg. or 20
deg. with much improvement.  In excessively
nervous people these spasms are quite frequent,
but when we have discovered beyond a perad-
venture where the abnormal innervation is,
we can force our position against all adverse
symptoms.
  AS THE CILIARY SPASM IN HYPEROPIA FRE-
QUENTLY PASSES BEYOND THAT POINT WHERE PERFECT
VISION IS THE RESULT, AND TOO HIGH A REFRACTION
OBTAINS (MYOPIA), SO WE MAY AS OFTEN EXPECT
THAT THE LONG MUSCLES, IN THEIR EFFORT TO
OVERCOME SOME ANATOMICAL DEFECT, HAVE
EXCEEDED THE INTENTION OF THEIR EFFORT TO
CORRECT, AND TURNED THE EYES IN A DIRECTION

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OPPOSITE TO THE SHORT MUSCLE.  THIS IS A
REVERSE-MANIFEST EYE-STRAIN AND VERY COMMON.
  When abnormal nerve-impulses have become
thoroughly established through the medium of
defects in the visual apparatus, and loss of sight
occurs, all means of repression through the
medium of the eyes is lost.  If abnormal impulses
depended upon a stimulus for their continuance,
blindness would be the end of them; but inasmuch
as these impulses become firmly and fixedly
established, they will not suspend themselves
without the interposition of repressive strain.
  When eyes deviate from parallelism, the
deflection is due to one of two causes, either a
short muscle or a spasm.  Again, the spasm may
be due to an effort to correct a short muscle or to
fixed abnormal nerve-impulses that are the out-
growth of long continued strained positions of
the eyes, as in writing, reading, painting, mining,
watchmaking and all kinds of labor where the eyes
are in constant use at the near point, or in some
unnatural position.





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        | End of Chapter X |  pages 153-164
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